Summers are really dry and hot in Pune. Two weeks ago I decided to buy an air cooler. There was a small temptation to invest in an air-conditioner but that idea was soon killed by the quantum of financial outlay and logic. Buying a cooler was easy on the pocket and easy on the logistical front.
Unpacking and installing took 10 minutes. I just had to fill the sump of the cooler and it was good to go. The very next second I could feel a pleasant blow of cool moist air. As I sat in front of the cooler, a strange disappointment settled in. The thing was loud. I decreased the fan speed to the lowest setting. It was still loud.
Several questions stirred in my mind. Why this darn machine needs to be so loud? why the lowest fan speed has to be so fast? Is there a better design for this? It is a reputed company, don’t they have any access to good R&D? I was no expert. I yielded to the complexity of the issue. There was no point in complaining now that I had already paid for the thing. For the next several days I lived in ignorance. The cool air was a pleasant relief after all. But the loudness was obviously a slight discomfort to my ears.
Yesterday as I was resting beside the cooler, I started to ponder upon the same questions which I had parked at the back of my mind. Why this darn thing needs to be so loud? is there no way around it? all the advancements in science are of no help? As I was thinking, I began to deconstruct the problem and then there was a spark of realization.
Air coolers work on a simple mechanism. They have a fan placed before a wet mesh. This mesh is maintained wet through a pumping mechanism. The pump draws water from the sump and continuously drops it on the mesh. Just imagine a giant fan behind which there is a waterfall. The fan not only throws cool air but evaporated particles of water which multiplies the cooling effect by two-fold. As a consequence, air-coolers are also called as humidifiers. The fan has to change the physical state of the liquid water to vapor and throw that vapor along with air at you so that you feel cool. That is evaporative cooling. That is the very reason you feel cool beside a lake or any other water body.
Now you don’t need to be a scientist or an engineer to know this. It is common sense.
What is not so obvious is the fact that the fan must have a minimum threshold speed to vaporize the water particles. And all this process has to take place in a box. That is how it works. It has to be loud.
Now that I had an answer to the dissonance of the cooler, should I say that things changed for me after that simple scientific revelation? Not really. But simple reasoning can help you to be at peace with your surroundings. I accept the cooler to a greater degree now.
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